Colloidal calcium phosphate is an essential part of casein micelles and being responsible for their stability.
Different mineralization of casein micelles was obtained by acidification of skim milk to pH 6.5, 6.0
or 5.5, followed by a dialysis method, using simulated milk ultrafiltrate without lactose, to obtain varying
levels of micellar calcium and phosphorus but constant value of pH, serum and free calcium, and serum
phosphorus. Bovine chymosin was added to the skim milk samples after dialysis and microstructural and
rheological properties during gel formation were recorded at 30 C. Samples after dialysis needed
approximately 30 min after the addition of chymosin to form rennet gels. In addition, low micellar
calcium and phosphorus values were both found to correlate with slightly less time for the gels to be
formed. This information highlights the importance of CCP in the primary phase of rennet gel formation.
The protein network of rennet gels after dialysis was more compact with many aggregates as demineralization
decreased. The small protein particles are able to increase the potential connection points
among proteins, support particle fusion and cause a compact structure.